Hole gauge



Dec, 8, 1953 J. H. DULLIGAN 2,651,540

HOLE GAUGE v Filed Nov. 13, 1950 mlmbimm Z7 T I J3 u 56 l" LL] 1I ,"Illm Snvgntor ,./aH/v H @ULL/GAN Gttorneg designate similar partsintheseveral views. u

Patented Dec. 8, 1953 UNITED STATES PATENT OFFICE HOLE GAUGE John H.Dulligan, South Gate, Calif.

Application November 13, 1950, Serial No. 195,219 2 claims. (ci.:as-17s)- This invention relates to measuring devices and deals moreparticularly with a device for measuring internal diameters.

Reference is made to applications Serial Nos. 239,151 and 239,152, bothilled July 28, 1951, the same being continuations in part of thisapplication.

The inspection of small holes such as drilled and small reamed holes, atthe present time, entails the use of a multiplicity of expensive gaugesof the go-no go type, even when the range of hole sizes is relativelysmall. While attempts have been made to provide diameter-measuring toolsfor the relatively large bores of cylinders, tubes, etc., there are notnow available satisfac tory inexpensive gauges to measure internaldiameters of holes of the order of the letter drill sizes. These lattersizes range between .234" and .413" and, while not intended as limiting,indicate the general range contemplated for the present gauge.

Accordingly, it is an object of the present invention to provide a holegauge more particularly adapted to measure relatively small holes, asabove indicated, in a manner to expedite inspection and to reduceexpense.

Whereas prior devices depended on oppositely directed pins to gauge ininternal diameter, the same, unless considerable time was used toyeifect at least two gauging operations for each hole, would giveinaccurate readings if the hole were not truly round. Also, if suchprior tools were not squarely entered into a hole, the angle ofpresentation to the hole would affect the reading. A further object ofthe invention, therefore, is to lprovide a hole gauge that automaticallycenters and squares itself in the hole being gauged and,

at all times, will give the same reading regard- A ing descriptionmerely describes embodiments of the present invention, which are givenby way of illustration or example only.

In the` drawings, like reference characters Fig. l is a longitudinalsectional view of a preferred form of hole gauge and embodying aconventional micrometer head, the latter being shown in elevation.

Fig. 2 is a broken sectional view of the gaugingr end of the gauge inanother position.

Fig. 3 is an end view of the gauge as in Fig. 2.

Fig. l is a cross-sectional view as taken on line 4-4 of Fig. 2.

Fig. 5 is a broken longitudinal sectional View of the gauge body. y

Fig. 6 is an enlarged Sectional View of a modiiicaton.

Fig. 'l is an end view of another modification.

Fig. 8 is an elevational View, in quarter section, of the gauge shown inFig. 7.

With particular reference to Figs. 1 to 5the gauge shown comprises,generally, a micrometer head ID having a stem I I, a conical tip I2 forthe end of said stem, a bodyv I3 connected to the micrometer head andgauge pieces I4 carried by by the body.

The micrometer head is generally conventional and comprises a barrel I5from the graduated end IE of which xedly extends stem II. While notshown, the stem, in that portion which is within barrel I5, is threadedand has threaded connection with sleeve II, which is concentric with thestem. It will be clear that relative rotation of the barrel and sleevewill result in relative axial movement of said barrel and sleeve. Forthe purposes of this disclosure, it is assumed that sleeve Il is xed andthat barrel I5 and stem I I revolve and move axially with respectthereto.

In the present case, stem II is provided with'a squaredv end I8 in whichis provided Aan axial socket I9. C'onical tip I2 has a shank 2B thattightly, yet removably, ts said socket, the tip having a squared end 2|that fits ilat against end I8 of the stem. The conical face 22 of thetip is outwardly directed and, in this case, the angle of said tip issuch that, in axial cross-section, the face is the hypotenuse of a righttriangle in which one leg is the radius at the base of face 22 and theother leg is a perpendicular height from said base to the apex 23 thatis twice the radius. Consequently, the diameter of the tip .base equalssaid perpendicular height.

The body I3 comprises a tubular member 24 provided at one end with asocket 25 into which sleeve i7 is accurately tted. A set screw 26 isused to removably mount tubular member 24 so that the same constitutes axed extension of sleevefI'l. vA` longitudinal bore 2'lffree1y accommentsintegrally extending from end wall 3I as; v

best seen in Fig. 5. Said segments snugly fit over the mentionedopposite end of tubular mein--v ber 24, abutting fdange 29. Theouterdiameter of housing 38 represents the smallest diametral size that thepresent gauge ca-nmeasures While four slots 32 are shown, the numbermayV vary as desired and may be increased as the Vdiametralsize of thebody is increased. An even number offsuch slots is desired' for a like'number of gauge pieces I4 so, that the gauge will have one or more pairsof' directly opposed' Vgauge pieces.V In order to keep the length ofhousing 30 as short asis practicable, the innerl side of endzwall 3Iisprovi'ded With a conicalc seat 34,into which the. apex 23 ofthe tipmay enter, asA shown in Fig. 2.

The gauge. pieces I4., are all exactly alike and comprise fiat elongatedelements that slidably nt in'` slots. 32. In this case, the gaugepieces, are coextensive in length with said sl'ots. Each gauge piece. I4is provided with a sloping face 35' formed at and conforming to theVangle of' slopev ofv conical face 22 of the tip I2. The outer edge 35`of each gauger piece i's provided with a shallow notch 3l.. Anexpandablespring band or ring 38 encircles the.` gauge pieces andresides in said notches. 3T., said ringV normally urging` the gaugepieces inwardly asY permitted by the tip I2. Notches 39 in the outercylindrical face of'housing 30 accommodate ring 38 when. the gaugepieces are in their innermost position in which their outerY edges. 36are. flush with the outer cylindrical face. of. the housing, as. in Fig.1.v

Itwill be. clear that the axial movement of tip I2 willresult in atransverse movement. of gauge pieces I4. and that said latter movement.is half as great asv the former. Thus,y the opposite. gauge piecestogether have. a transverse movement exactly equal to the axial movementof the tip.

In order that the gauge pieces move only laterally whenY wedged apart bylthe tip, means are provided to obviate any angular or longitudinalmovement of said gaugey pieces. As shown, such means comprises alaterally directed tongue 40 on each gauge piece and a slideway 4Iopening into4 each slot 32 and guiding said tongues. Y

When the tip I2 is Withdrawn againstl face. 28' of member 24, springring 38 Will retractv gauge Ipieces I4 to the smallest measuringposition of j Fig. 1, and the reading onv the micrometer head I will bezero as shown'. v turned, the expanded measurement across the oppositegauge lpieces will be read-directly onV the When barrel I is micrometerhead inthe usual way. Thus, .by inserting thefhousing Iend of the gaugerin a hole, holding themember 24, and turning Vbarrel I5 until the gaugepieces are kstopped bythe walli -of the hole, the exact sizeof thelatter is shown by the -graduations on the micrometer head.'`

In themodication of Fig. 6, the body isv amxed to. member 24 inthe.same, .Way as is vbody .3.0. In. Y this case, however.' the body isprovided with' a conical face 5I from which a set of segments 53extends, the same being defined by longitudinal slots 54 comparable toslots 32. The stem II, in this case, is provided with an elongatedextension rod 55 on the end of which is affixed a cone 56 having aconical face 51 equal and opposite to face 5I.

Conical faces 5I and 5l are on a one-to-one angle or slope rather than.on theV one-to-two slope of conical' face 22". The gauge pieces 58 iitslots 54 and each has angularly directed faces `5,5 and 60 at the angleof the respective conical faces 5I and 51 and held in engagement withsaielfaces by spring rings or bands 5I comparable te rings 38.,

It will be seen that axial movement of the stems I'I relative to2housing 50 will cause transverse movement of gauge pieces 55 by movingcone 5'5'toward or away from conical face 5I. In this case, there is anendwise shift of the gauge'pieces relative to the housing. Hence, theone-to-one slope of f-aces 5I andv 5T. The reading on the micrometerhead is made asl before.

Inthe modification of Figs. 'If and 8; the tip '|50 on stem II extendsbeyond the end ofv member 24 and the housings 30 or 50 are omitted. Inthiscase, said tip is reversed from theti'pf'off the form in- Fig. 1,but the slope thereof' is'` the same. Instead of separate gauge piecesf`I4' or 55, an annular andl endless helically coiled means 'H encirclestip It), the same having outer gauging coil portions 'I-2 that arecylindrieallyl arranged and inner sloping tip-engaging coil' portions I3at the angle of the slope of tip 751. Said means 'II isr formed ofspring wire of' round or square section, asY desired, the coils thereofexpanding and contractingy according to the endwise movement of tip I8relative to end' shoulder T4'- of member 2-4". The angle of slope of tipT0 i's the same as that of tip I2 so that the diametralexpansionl ofcoil portions 'l2v equals the axial movement of tip 'I8 as in the 'rstform of the invention.

While the invention-that has been illustrated and described is nowregarded as theY preferred embodiments, the constructions are, ofcourse, subject to` modifications without departing from the spirit and:scope of the invention. It' is'therefore not desiredn to restrict theinvention to the particular forms of-v construction illustrated anddescribed, but tocoverall modifications that may fall within the scopeof the appended' claims.

Having thus described the invention, what is claimed and desired to. besecured by' Letters Patent is:

l. In a hole gauge having a lmicrometer 'head provided witha fixedsleeve and an axially movable stem extending concentrically from saidsleeve and with an elongated 'body affixed' `to the sleeve andhaving abore through which the stem extends, there being, a conical tip. on the`end of said-stem and beyond' the end'of' said body., the apex ofr saidtip being outwardly directed, the improvement' that comprises a tubularhousing around the tip connected to and forming an extension of theelongated body, .an end wall on said Vhousingformed with ,a conicalrecess Vto receive the apex of said tip When projected in a directionaway from Vthe end of the elongated body, the tubular wall ofk the'tubular housing comprising a set of segments defined by Vlongitudinalslots that extend forthe entire length of the housing, the yends .of the'segments opposite theend Wallof the housing tting over the' end of theelongated body, a set of gauge pieces each equal in length to theoverall length of the housing and residing in the slots in said housing,each gauge piece having a sloping edge face at an angle conforming tothe angle of the conical tip, means encircling the set of gauge piecesand resiliently urging the sloping edge faces thereof into engagementwith the tip, and a lateral projection on each gauge piece, there beinga lateral slideway in each segment to slidingly guide the gauge piecesduring transverse movement of said pieces as controlled by the movementof the tip.

2. In a hole gauge according to claim 1: the lateral projections on thegauge pieces being spaced fordwardly from the sloping edge faces of saidpieces.

JOHN H. DULLIGAN.

References Cited in the le of this patent UNITED STATES PATENTS NumberNumber Name y Date 1,554,226 Martell Sept. 22, 1925 1,760,717 Peglow May27, 1930 2,047,607 Zimmerman July 14, 1936 2,135,912 Rae NOV. 8, 19382,358,749 Volis et al Sept. 19, 1944 FOREIGN PATENTS Number Country Date224,234 Switzerland June 1, 1943 336,996 Germany May 21, 1921 524,392France Sept. 2, 1921 582,941 Great Britain Dec. 3, 1946 612,457 GreatBritain Nov. 12, 1948 OTHER REFERENCES Publ.: Industrial InspectionMethods; page 164, Fig. 8.20 by L. C. Michelon, published by Harper &Bros.

